1. Technical Field
The present invention relates generally to commercial motor vehicles and more particularly to an automated system for indicating imminent failure of a high intensity discharge lamp.
2. Description of the Problem
Metal halide high intensity discharge (HID) lamps have made great inroads in automobile applications in recent years, but have not proven quite so popular in truck and heavy duty commercial vehicle applications. Traditionally no provision has been made for predicting lamp failure in vehicles because of the wide statistical variance in occurrences of failure. However, three wire HID ballasts generate a signal on one line which varies with ballast age and relative imminence of ballast shutdown.